Natural history of premature thelarche.

Fifty-nine girls with premature thelarche who attended the endocrine clinic at Children's hospital from 1980 to 1984 were studied. These girls were followed up for at least 3 years. The onset of premature thelarche was found in every age group from birth to below 96 months of age. Approximately 50 per cent of the cases had the onset between the age of 19 months and 96 months. In 44.1 per cent breast enlargement was unilateral. Forty-three patients (72.9%) had persistent breast enlargement for 3 years or more. Sixteen patients (27.1%) had progressive breast enlargement and 45.8 per cent had unchanged breast size at the time of the study. Premature thelarche resolved completely in 16 cases. The duration of regression ranged from 3-60 months, with a mean of 23 months. Premature thelarche is a benign condition but physicians must be cautious when predicting the outcome of breast enlargement. Periodic examination is essential to detect the other pubertal signs and do further investigations as necessary.